1. Field of the Invention
The present invention relates to a method for transmitting a signal with a signal transmission rate selected from a plurality of signal transmission rates. The method according to the present invention is used, for example, in a facsimile transmission system.
2. Description of the Prior Art
In general, in facsimile systems using the telephone exchange network, modulation/demodulation devices, called MODEMs, having a plurality of signal transmission rates are used. The transmission rate with which the picture signal transmission can be carried out at the highest speed with the least distortion of picture signal is selected before the start of the transmission, and the transmission of the picture signal is carried out with the above-selected transmission rate.
However, in the prior art facsimile system, a problem arises wherein the decision of the suitable signal transmission rate sometimes takes a considerable length of time, so that the start of the transmission of the picture signal with such a decided transmission rate tends to be delayed.
Some of the prior art facsimile transmission systems are disclosed in, for example, the following publications:
(1) Japanese Unexamined Patent Publication (Kokai) No. 53-8010; and
(2) Japanese Unexamined Patent Publication (Kokai) No. 57-5465.